Multipath effectuation within singly contiguous network fabric via switching device routing logic programming

ABSTRACT

Each of a network fabric controller device and a network fabric forwarder devices includes network connecting hardware and network managing logic. The network connecting hardware of the devices connects them to a singly contiguous network fabric including switching devices that route data between initiator nodes and target nodes and that have routing logic programmable by the controller device. The controller device does not directly route the data themselves. The network managing logic of the devices effects multipaths for transmission of the data through the singly contiguous network fabric from the initiator node to the target nodes via programming of the routing logic of the switching devices.

RELATED APPLICATIONS

The present patent application is a continuation of the pending patentapplication Ser. No. 13/827,479, filed on Mar. 14, 2013, which is acontinuation of the pending patent application Ser. No. 13/485,428,filed on May 31, 2012. The present patent application is further relatedto the patent application entitled “end-to-end multipathing throughnetwork having switching devices compatible with different protocols,”filed on Mar. 14, 2013, and assigned application Ser. No. 13/829,124.

BACKGROUND

Network fabrics include devices, which are often referred to as nodes,that are interconnected to one another through a web of variousswitching devices like routers, hubs, switches, and so on. The networkfabrics permit the devices to be interconnected for a variety ofdifferent purposes. For instance, the devices may be interconnected toimplement a local-area network or a wide-area network for datatransmission purposes, to implement a storage-area network, to achieveclustering, and so on.

SUMMARY

A method of an embodiment of the disclosure is performed responsive to anetwork fabric login request initiated by a given initiator node. Thefollowing is performed by a network fabric forwarder device. A networkfabric port and a network fabric address for the given initiator nodeare created. A list of one or more network fabric ports of one or moregiven target nodes associated with the given initiator node is acquired.A network fabric address for the given target node of each networkfabric port within the list is determined. One of the following isperformed by a network fabric controller device, using the networkfabric addresses of the given initiator node and of the given targetnodes. One or more paths between the given initiator node and the giventarget nodes through a singly contiguous network fabric can bedetermined, and the paths loaded into a forwarding table of eachswitching device of switching devices of the singly contiguous networkfabric. A path between the given initiator node and a network fabricforwarding component connected to the switching devices through thesingly contiguous network fabric can be determined, and the path loadedinto a forwarding table of each switching device within the path.

As such, multipaths for transmission of data through the singlycontiguous network fabric from the given initiator node and the giventarget nodes are effected. The network fabric forwarder device and thenetwork fabric controller device are each control-path connected to eachswitching device. The network fabric controller device does not directlyroute the data; the switching devices do route the data between thegiven initiator node and the given target nodes.

A method of another embodiment of the disclosure is performed responsiveto a network fabric login request initiated by a given target node. Thefollowing is performed by a network fabric forwarder device. A networkfabric port and a network fabric address for the given target node arecreated. A list of one or more fabric network ports of one or more giveninitiator nodes associated with the given target node is acquired. Anetwork fabric address for the given initiator node of each networkfabric port within the list is determined. One of the following isperformed by a network fabric controller device, using the networkfabric address of the given target node and of the given initiatornodes. One or more paths between the given initiator nodes and the giventarget node through a singly contiguous network fabric can bedetermined, and the paths loaded into a forwarding table of eachswitching device of switching devices of the singly contiguous networkfabric. One or more paths between the given initiator nodes and anetwork fabric forwarding component connected to the switching devicesthrough the singly contiguous network fabric can be determined, and thepaths loaded into a forwarding table of each switching device within thepaths.

As such, multipaths for transmission of data through the singlycontiguous network fabric from the given initiator nodes and the giventarget node are effected. The network fabric forwarder device and thenetwork fabric controller device are each control-path connected to eachswitching device. The network fabric controller device does not directlyroute the data; the switching devices do route the data between thegiven initiator nodes and the given target node.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The drawings referenced herein form a part of the specification.Features shown in the drawing are meant as illustrative of only someembodiments of the invention, and not of all embodiments of theinvention, unless otherwise explicitly indicated, and implications tothe contrary are otherwise not to be made.

FIGS. 1A and 1B are diagrams of example networking topologies.

FIG. 2 is a diagram of an example logic depiction of a network fabric.

FIGS. 3A and 3B are diagrams of different example multipaths throughdifferent example singly contiguous network fabrics.

FIGS. 4A and 4B are flowcharts of example methods by which multipathingcan be effected through a singly contiguous network fabric.

FIG. 5 is a diagram of an example implementation of a network fabricforwarder or controller device.

DETAILED DESCRIPTION

In the following detailed description of exemplary embodiments of theinvention, reference is made to the accompanying drawings that form apart hereof, and in which is shown by way of illustration specificexemplary embodiments in which the invention may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilized,and logical, mechanical, and other changes may be made without departingfrom the spirit or scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the embodiment of the invention is defined only by theappended claims.

As noted in the background section, a network fabric includes devices,which can be referred to as nodes, that are interconnected to oneanother through a web of various switching devices like routers, hubs,switches, and so on. As such, the nodes can communicate with one anotherby transmitting data through the network fabric, and more specificallyvia the switching devices routing the data between the nodes. Switchingdevices, however, can fail, and a network fabric can otherwise besusceptible to faults that prevent data from being successfully routedamong the nodes.

Therefore, it can be important to have multiple redundant paths througha network fabric, to ensure that data is successfully routed among nodeseven in the presence of faults such as switching device failure. Oneapproach to achieving this is to have two or more physicallydiscontiguous networks within a given network fabric, with redundantswitching devices in each such network. Therefore, if a particularnetwork suffers from a fault, a different network can still be used torealize communication through the network fabric. However, maintainingsuch physically discontiguous networks can be overly expensive in termsof the time and cost involved in configuring, managing, and maintainingthese networks.

Another approach is to provide for multipathing within a singlycontiguous network fabric. In a singly contiguous network fabric, thereis just one physically contiguous network of switching devices.Multipathing ensures that there are different paths between two givennodes through the network fabric. The multipaths themselves can bedisjoint or shared. Shared multipaths have one or more switching devicesin common, but still vary from one another. Disjoint multipaths have noswitching devices in common, by comparison. Multipathing in a singlycontiguous network fabric provides for the advantages of having two ormore physically discontiguous networks, without the associateddisadvantages.

Techniques disclosed herein provide for innovative approaches torealizing multipathing within a singly contiguous network fabric. Thesetechniques employ a network fabric controller device and a networkfabric forwarder device that can be implemented within the same physicaldevice or at separate physical devices. The network fabric controllerdevice does not directly route data itself. Switching devices within thenetwork fabric are primarily responsible for routing data among nodes,although the network fabric forwarder device may also be responsible forrouting data. The switching devices have routing logic that isprogrammable by the network fabric controller device, such that thenetwork fabric controller device and the network fabric forwarder devicetogether can effect multipaths for transmission of data through thesingly contiguous network fabric among the nodes, via suitablyprogramming at least the routing devices, and also network fabricforwarder device when appropriate.

In this respect, in one implementation the network fabric forwarderdevice can be a fiber channel (FC) or fiber channel over Ethernet (FCoE)channel forwarder (FCF) device in FC and FCoE network fabrics that mayalso employ FC or FCoE data-plane forwarder (FDF) devices. In suchnetwork fabrics, the FDF devices work with the switching devices, or areor are replaced by the switching devices, to route data through thefabrics. By comparison, the FCF devices control the FDF devices, but donot route the actual data themselves.

Furthermore, in one implementation the network fabric controller devicecan be an OpenFlow controller (OFC) device. An OFC device is employed inthe context of the OpenFlow protocol maintained by the Open NetworkingFoundation of Palo Alto, Calif. The OpenFlow protocol permits anOpenFlow switch, or switching device, to be completely programmed by anOFC device. An OFC device thus can program OpenFlow switching devices toperform data routing as desired. While the control of the switchingdevices remains under the auspices of FCF devices in the context of anFC or an FCoE network fabric, the switching devices are programmed bythe OFC device.

Therefore, in implementations in which the network fabric controllerdevice is an OFC device, the network fabric forwarder device is an FCFdevice, and the switching devices are OpenFlow switching devices like orincluding FDF devices, the FCF device provides control informationregarding the switching devices to the OFC device. In turn, the OFCdevice uses this control information to appropriately program theOpenFlow switching devices. Therefore, it is said that the OFC and FCFdevices together effect multipaths for data transmission through thesingly contiguous network fabric. Although it is the OFC device thatactually programs the switching devices to achieve such multipathing,the OFC device performs this programming on the basis of controlinformation that the FCF device provides.

FIGS. 1A and 1B show two example networking topologies. The networkingtopologies of FIGS. 1A and 1B both include a singly contiguous networkfabric 102, switching devices 104, initiator nodes 106, target nodes108, a network fabric forwarder device 110, and a network fabriccontroller device 112. In FIG. 1B, the switching devices 104 includeswitching devices 104A and switching devices 104B, which arecollectively referred to as the switching devices 104. In the networkingtopologies of both FIGS. 1A and 1B, the switching devices 104 areconsidered as part of the network fabric 102, whereas in FIG. 1B theforwarder device 110 may also be considered as part of the networkfabric 102.

Transmission of data within the networking topologies of FIGS. 1A and 1Bis depicted by solid lines among the switching devices 104, theinitiator nodes 106, and the target nodes 108. Transmission of controlinformation within the networking topologies of FIGS. 1A and 1B isdepicted by dashed lines between the switching devices and the networkfabric forwarder device 110. Transmission of programming informationwithin the networking topologies of FIGS. 1A and 1B is depicted bydotted lines among the switching devices 104, the forwarder device 110,and the network fabric controller device 112. The distinction betweendata, control information, and programming information is describedlater in the detailed description.

In the networking topology of FIG. 1A, data between the initiator nodes106 and the target nodes 108 may be routed within the singly contiguousnetwork fabric 102 just among the switching devices 104, and notnecessarily through the network fabric forwarder device 110. Bycomparison, in the networking topology of FIG. 1B, data between theinitiator nodes 106 and the target nodes 108 is routed within thenetwork fabric 102 among the switching devices 104 and the forwarderdevice 110. For example, data originating at an initiator node 106 andintended for a target node 108 is transmitted through the network fabric102 from one or more switching devices 104A to the forwarder device 110,and then from the forwarder device 110 to one or more switching devices104B.

As noted above, the singly contiguous network fabric 102 is singlycontiguous in that there is just one physically contiguous network ofswitching devices 104, as opposed to two or more physicallydiscontiguous networks of redundant switching devices. The networkfabric 102 can be an FC, an FCoE, or another type of network fabric. Thenetwork fabric 102 can implement a storage-area network, a local-area ora wide-area network for data transmission purposes, a network to achieveclustering, or another type of network.

The switching devices 104 can include routers, hubs, switches, and othertypes of switching devices. For instance, where the singly contiguousnetwork fabric 102 is an FC or an FCoE network fabric, the switchingdevices 104 can include FDF devices. The FDF devices are typicallylocated at edges of the network fabric 102, and are directly connectedto the initiator nodes 106 and the target nodes 108. The FDF devices canthen be interconnected to other types of switching devices 104, likerouters or switches in particular, located within the interior and notat the edge of the network fabric 102.

The initiator nodes 106 can be logical, virtual, physical, and/ordiscrete devices, such as computing devices like servers, clientcomputers and other types of client computing devices, and so on, thatgenerally initiate data requests in relation to the target nodes 108.The target nodes 108 can be logical, virtual, physical, and/or discretedevices, also such as computing devices like servers, client computersand other types of client computing devices, and so on, that generallyreceive the data requests from the initiator nodes 106. For example, inthe context of a storage-area network, the target nodes 106 may be orinclude storage devices that store data for or on behalf of theinitiator nodes 106.

The network fabric forwarder device 110 may be an FCF device where thesingly contiguous network fabric 102 is an FC or an FCoE network fabric,for instance. An FCF device can but does not necessarily route datawithin the network fabric 102. For instance, in FIG. 1B, the forwarderdevice 110 does route data within the network fabric 102, whereas inFIG. 1A, the forwarder device 110 may route data within the networkfabric 102. An FCF device is responsible for controlling other deviceswithin the network fabric 102, particularly the switching devices 104.In this respect, an FCF device receives, maintains, and manages controlinformation from and of the switching devices 104, such as which portsof which switching devices 104 are connected to which parts of whichother switching devices 104 and to which ports of the initiator nodes106 and of the target nodes 108, and so on.

The network fabric controller device 112 may be an OFC device where theswitching devices 104 and/or the network forwarder device 110 areOpenFlow devices. An OFC device can program the switching devices 104,for example, so that they achieve desired routing. This is described inmore detail later in the detailed description. However, in general,although the switching devices 104 may have hardware to provide for fastrouting of data between the initiator nodes 106 and the target nodes108, how the switching devices 104 perform this routing is controlled bysoftware thereof that is programmable by the OFC device. The controllerdevice 112 does not route data within the singly contiguous networkfabric 102, and does not directly receive control information from theswitching devices 104, but rather indirectly receives such controlinformation via the network fabric forwarder device 110.

In the techniques disclosed herein, the network fabric controller device112 programs the switching devices 104 to effect multipathing betweenthe initiator nodes 106 and the target nodes 108. This programming isbased on the control information acquired by the network forwarderdevice 110 from the switching devices 104 and passed to the controllerdevice 112. Therefore, in general, the forwarder device 110 communicateswith the switching devices 104 to acquire control information, andpasses this information to the controller device 112. On the basis ofthe control information, the controller device 112 determines multipathsthrough the network fabric 102, and suitably programs at least theswitching devices 104 (and also the forwarder device 110 whereappropriate, when the forwarder device 110 also routes data through thenetwork fabric 102).

The network fabric forwarder device 110 and the network fabriccontroller device 112 can be implemented as separate computing devices,or within the same computing device, such as within the same server. Thenetwork fabric forwarder device 110 can also be referred to as a networkfabric forwarder component, and likewise the network fabric controllerdevice 112 can also be referred to as a network fabric controllercomponent. In this respect, for example, a single computing device canbe said to include both the network fabric forwarder component and thenetwork fabric controller component.

FIG. 2 logically depicts the example singly contiguous network fabric102. The network fabric 102 logically includes three paths or channels:a data path or channel 202, a control path or channel 204, and aprogrammable path or channel 206. The data path or channel 202, thecontrol path or channel 204, and the programmable path or channel 206are respectively depicted in FIG. 2 as corresponding to solid, dashed,and dotted lines, in accordance with FIGS. 1A and 1B.

The data path or channel 202 is the path or channel of the singlycontiguous network fabric 102 along which data is transmitted betweenthe initiator nodes 106 and the target nodes 108. The control path orchannel 204 is the path or channel of the network fabric 102 along whichcontrol information regarding components of the network fabric 102, suchas at least the switching devices 104, is transmitted. This controlinformation can include port information, address information, and othertypes of control information regarding these components. The controlinformation can include, or can be used to determine, how the componentsof the network fabric 102 are interconnected to one another, forinstance.

The programming path or channel 206 is the path or channel of the singlycontiguous network fabric 102 by which components of the network fabric102, such as at least the switching devices 104, are programmed. Forinstance, the network fabric controller device 112 can load routingtables and/or other types of programming logic into the switchingdevices 104. As such, the controller device 112 effectively can controlhow the switching devices 104 route the data through the network fabric102 between the initiator devices 106 and the target nodes 108.

The paths or channels 202, 204, and 206 may be logical/virtual orphysically discrete paths or channels. For example, there may indeed bejust single hardware lines interconnecting the switching devices 104,the network fabric forwarder device 110, and the controller device 112.However, these hardware lines may have the various paths or channels202, 204, and 206 virtually or logically overlaid thereon or definedtherein. For instance, the programming path or channel 206 may be asecure socket layer (SSL) channel that uses the same hardware lines thatthe data path or channel 202 uses.

The switching devices 104 typically can provide fast routing of datathrough the network fabric 102 over the data path or channel 202. Inthis respect, the switching devices 104 may have dedicated routinghardware to achieve high-performance routing. The switching devices 104have firmware or other software that is programmable by the networkfabric controller device 112, though, such as in accordance with theOpenFlow protocol. Therefore, the switching devices 104 may berelatively low cost, so-called “dumb” switching devices that do not havemuch if any built-in logic, and instead are programmed and controlled byan external device like the controller device 112.

FIGS. 3A and 3B show different examples of multipathing through a singlycontiguous network fabric 102. The network fabric 102 of FIG. 3A is aparticular representative example of the networking topology of FIG. 1A.Similarly, the network fabric 102 of FIG. 3B is a particularrepresentative example of the networking topology of FIG. 1B.

In FIG. 3A, the singly contiguous network fabric 102 includes nineswitching devices 302A, 302B, 302C, 302D, 302E, 302F, 302G, 302H, and302I, which are collectively referred to as the switching devices 302,and which correspond to the switching devices 104 of FIG. 1A. Each ofthe switching devices 302A, 302B, and 302C is connected to an initiatornode 106 and to each of the switching devices 302D, 302E, and 302F. Eachof the switching devices 302D, 302E, and 302F is connected to a targetnode 108 and to each of the switching devices 302G, 302H, and 302I.

Data originating at the initiator node 106 is transmitted through thesingly contiguous network fabric 102 to the target node 108. Threeexample multipaths 304, 306, and 308 between the initiator node 106 andthe target node 108, along which the data can be transmitted through thenetwork fabric 102, are shown in FIG. 3A. The multipath 304 includes theswitching devices 302A, 302D, and 302G. The multipath 306 includes theswitching devices 302B, 302E, and 302H. The multipath 308 includes theswitching devices 302C, 302E, and 302I.

The multipaths 304 and 306 are disjoint multipaths in relation to oneanother, because the multipaths 304 and 306 do not share any switchingdevice 302. That is, the switching devices 302A, 302D, and 302G of themultipath 304 are mutually exclusive with the switching devices 302B,302E, and 302H of the multipath 306. By comparison, the multipaths 306and 308 are shared multipaths in relation to one another, because themultipaths 306 and 308 share one or more switching devices 302. Inparticular, the multipaths 306 and 308 share the switching device 302E.

In FIG. 3B, the singly contiguous network fabric 102 includes twelveswitching devices 302A, 302B, 302C, 302D, 302E, 302F, 302G, 302H, 302I,302J, 302K, and 302L, which are collectively referred to as theswitching devices 302. The switching devices 302A, 302B, 302C, 302D,302E, and 302F correspond to the switching devices 104A of FIG. 1B. Theswitching devices 302G, 302H, 302I, 302J, 302K, and 302L correspond tothe switching devices 104B of FIG. 1B.

Each of the switching devices 302A, 302B, and 302C is connected to aninitiator node 106 and to each of the switching devices 302D, 302E, and302F. Each of the switching devices 302D, 302E, and 302F is connected tothe network fabric forwarder device 110, which is part of the singlycontiguous network fabric 102 in FIG. 3B. Each of the switching devices302G, 302H, and 302I is connected to the forwarder device 110 and toeach of the switching devices 302J, 302K, and 302L. Each of theswitching devices 302J, 302K, and 302L is connected to a target node108.

Data originating at the initiator node 106 is transmitted through thesingly contiguous network fabric 102 to the target node 108. Threeexample multipaths 310, 312, and 314 between the initiator node 106 andthe target node 108, along which the data can be transmitted through thenetwork fabric 102, are shown in FIG. 3B. The multipath 310 includes theswitching devices 302A, 302D, 302G, and 302J, as well as the networkfabric forwarder device 110. The multipath 312 includes the switchingdevices 302B, 302E, 302H, and 302K, as well as the forwarder device 110.The multipath 314 includes the switching devices 302C, 302E, 302H, and302L, as well as the forwarder device 110.

As to just the switching devices 302, and not also as to the networkfabric forwarder device 110, the multipaths 310 and 312 are disjointmultipaths in relation to one another, because the multipaths 310 and312 do not share any switching device 302. That is, the switchingdevices 302A, 302D, 302G, and 302J of the multipath 310 are mutuallyexclusive with the switching devices 302B, 302E, 302H, and 302K of themultipath 312. By comparison, as to just the switching devices 302, andnot also as to the network fabric forwarder device 110, the multipaths312 and 314 are shared multipaths in relation to one another, becausethe multipaths 312 and 314 share one or more switching devices 302. Inparticular, the multipaths 312 and 314 share the switching devices 302Eand 302H.

FIGS. 4A and 4B show example methods 400 and 450 by which the networkfabric forwarder device 110 and the network fabric controller device 112can collaboratively effect multipathing between the initiator nodes 106and the target nodes 108 through the singly contiguous network fabric102. The method 400 of FIG. 4A is performed responsive to a networkfabric login request received from an initiator node 106, whereas themethod 450 of FIG. 4B is performed responsive to a network fabric loginrequest received from a target node 108. The methods 400 and 450 aredescribed both generally and in relation to a specific implementation inwhich the network fabric 102 is an FC or an FCoE network fabric.

In FIG. 4A, the network fabric forwarder device 110 receives a networkfabric login request issued by an initiator node 106 (402). The networkfabric login request can be an FC or FCoE initialization protocol (FIP)fabric login (FLOGI) request. In response, the forwarder device 110creates a fabric network port and a fabric network address for theinitiator node 106 (404). The fabric network port can be an FC N_Portidentifier (ID). The fabric network address can be an Ethernet (Enet)fiber-provided media-access controller (MAC) address (FPMA).

The network fabric forwarder device 110 acquires a list of fabricnetwork ports of target nodes 108 associated with the initiator node 106(406), via the control path or channel 204 of the singly contiguousnetwork fabric 102. The fabric network ports can be FC N_Port IDs. Thesefabric network ports can be associated with the worldwide port name(WWPN) for the initiator node 106, and may be provided in a fabricnetwork frame, such as an FC or an FCoE frame.

For the target node 108 of each fabric network port, the network fabricforwarder device 110 determines a network fabric address (408). Forinstance, the forwarder device 110 can compute the Enet FPMA associatedwith each FC N_Port ID. The forwarder device 110 may cache thisinformation so that the forwarder device 110 does not have to recomputethe information later. The forwarder device 110 sends the network fabricports and the network fabric addresses of the initiator node 106 and ofthe target nodes 108 in question to the network fabric controller device112 (410), which receives this information (412).

The network fabric controller device 112 determines multiple paths toeffect multipathing between the initiator node 106 and these targetnodes 108 by performing one of the following using the provided networkfabric addresses and network fabric ports (414). First, the controllerdevice 112 can determine a path from the initiator node 106 to eachtarget node 108, and via the programming path or channel 206 of thesingly contiguous network fabric 102, load the paths into each switchingdevice 104 within the network fabric 102 (416). For instance, thecontroller device 112 can determine a path from the Enet FPMA of theinitiator node 106 to the Enet FPMA of each associated target node 108.The controller device 112 may employ an equal-cost multipath (ECMP)algorithm, or another type of approach, to determine the paths. Part 416can be particularly used in conjunction with the networking topology ofFIG. 1A.

Second, the network fabric controller device 112 can determine a pathfrom the initiator node 106 to the network fabric forwarder device 110,and via the programming path or channel 206 of the singly contiguousnetwork fabric 102 load the path into each switching device 104 withinthis path (418). For instance, the controller device 112 can determine apath from the Enet FPMA of the initiator node 106 to the forwarderdevice 110. Part 418 can be particularly used in conjunction with thenetworking topology of FIG. 1B. Upon effecting the multipathing of part414, the controller device 112 signals completion to the forwarderdevice 110 (420), which responsively issues a response to the initiatornode 106 (422), indicating that the initiator node 106 can now commencewith communication through the network fabric 102.

Parts 416 and 418 thus result in the network fabric controller device112 programming the switching devices 104 based on information providedby the network fabric forwarder device 110, to achieve disjoint orshared multipathing (as desired) between an initiator node 106 and itsassociated target nodes 108. Thereafter, when the initiator node 106sends data to the target nodes 108 through the network fabric 102, thedata travels along one of the multipaths that have been programmedwithin the switching devices 104. If one multipath suffers a fault, adifferent multipath can be used.

More specifically, part 416 provides for multipathing as follows. Part416 can be performed multiple times to determine a number of paths fromthe initiator node 106 and each associated target node 108, from whichthe network fabric controller device 112 can determine which paths aredisjoint or shared multipaths as desired to program into the switchingdevices 104. Part 418 similarly provides for multipathing. Part 418 canbe performed multiple times to determine a number of paths, both betweenthe initiator node 106 and the network fabric forwarder device 110, andbetween the forwarder device 110 and each associated target node 108.The controller device 112 can then determine which paths are disjoint orshared multipaths as desired to program into the switching devices 104.

In FIG. 4B, the network fabric forwarder device 110 receives a networkfabric login request issued by a target node 108 (452). The networkfabric login request can be an FLOGI request. In response, the forwarderdevice 110 creates a fabric network port and a fabric network addressfor the target node 108 (454). The fabric network port can be an FCN-Port ID. The fabric network address can be an Enet FPMA.

The network fabric forwarder device 110 acquires a list of fabricnetwork ports of initiator nodes 106 associated with the target node 108(456), via the control path or channel 204 of the singly contiguousnetwork fabric 102. The fabric network ports can be FC N-Port IDs. Thesefabric network ports can be associated with the WWPN for the target node108, and may be provided in a fabric network frame, such as an FC or anFCoE frame.

For the initiator node 106 of each fabric network port, the networkfabric forwarder device 110 determines a network fabric address (458).For instance, the forwarder device 110 can compute the Enet FPMAassociated with each FC N_Port ID. The forwarder device 110 may cachethis information so that the forwarder device 110 does not have torecompute the information later. The forwarder device 110 sends thenetwork fabric ports and the network fabric addresses of the initiatornodes 106 in question and of the target node 108 to the network fabriccontroller device 112 (460), which receives this information (462).

The network fabric controller device 112 determines multiple paths toeffect multipathing between the target node 108 and the initiator nodes106 by performing one of the following using the provided network fabricaddresses and network fabric ports (464). First, the controller device112 can determine a path from each initiator node 106 to the target node108, and via the programming path or channel 206 of the singlycontiguous network fabric 102, load the paths into each switching device104 within the network fabric 102 (466). For instance, the controllerdevice 112 can determine a path from the Enet FPMA of each associatedinitiator node 106 to the Enet FPMA of the target node 108. Thecontroller device 112 may employ an ECMP algorithm, or another type ofapproach to determine the paths. Part 466 can be particularly used inconjunction with the networking topology of FIG. 1A.

Second, the network fabric controller device 112 can determine a pathfrom each associated initiator node 106 to the network fabric forwarderdevice 110, and via the programming path or channel 206 of the singlycontiguous network fabric 102 load the path into each switching device104 within the path (468). For instance, the controller device 112 candetermine a path from the Enet FPMA of each such initiator node 106 tothe forwarder device 110. Part 468 can be particularly used inconjunction with the networking topology of FIG. 1B. Upon effecting themultipathing of part 464, the controller device 112 signals completionto the forwarder device 110 (470), which responsively issues a responseto the target node 108 (472), indicating that the target node 108 cannow commence with communication through the network fabric 102.

Parts 466 and 468 thus result in the network fabric controller device112 programming the switching devices 104 based on information providedby the network fabric forwarder device 110, to achieve disjoint orshared multipathing (as desired) between a target node 108 and itsassociated initiator nodes 106. Thereafter, when the target node 108sends data to the initiator nodes 106 through the network fabric 102,the data travels along one of the multipaths that have been programmedwithin the switching devices 104. If one multipath suffers a fault, adifferent multipath can be used.

More specifically, part 466 provides for multipathing as follows. Part466 can be performed multiple times to determine a number of paths fromeach associated initiator node 106 and the target node 108, from whichthe network fabric controller device 112 can determine which paths aredisjoint or shared multipaths as desired to program into the switchingdevices 104. Part 468 similarly provides for multipathing. Part 468 canbe performed multiple times to determine a number of paths, both betweeneach associated initiator node 106 and the network fabric forwarderdevice 110, and between the forwarder device 110 and the target node108. The controller device 112 can then determine which paths aredisjoint or shared multipaths as desired to program into the switchingdevices 104.

FIG. 5 shows an example implementation of a device 500 that representsthe network fabric forwarder device 110 or the network fabric controllerdevice 112. The device 500 includes network connecting hardware 502 andnetwork managing logic 504. The device 500 can also include othercomponents, in addition to the networking connecting hardware 502 and/orthe network managing logic 504. The network connecting hardware 502 ishardware that connects the device 500 to the singly contiguous networkfabric 102.

The network managing logic 504 performs the functionality ascribed tothe network fabric forwarder device 110 in the case where the device 500represents the forwarder device 110, and performs the functionalityascribed to the network fabric controller device 112 in the case wherethe device 500 represents the controller device 112. The networkmanaging logic 504 may be implemented as software, hardware, or acombination of software and hardware. As one example, the networkmanaging logic 504 may be a computer program stored on acomputer-readable data storage medium and executable by a processor. Asanother example, the network managing logic 504 may be implemented ashardware, such as an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA), and so on.

It is noted that, as can be appreciated by one those of ordinary skillwithin the art, aspects of the present invention may be embodied as asystem, method or computer program product. Accordingly, aspects of theembodiments of the invention may take the form of an entirely hardwareembodiment, an entirely software embodiment (including firmware,resident software, micro-code, etc.) or an embodiment combining softwareand hardware aspects that may all generally be referred to herein as a“circuit,” “module” or “system.” Furthermore, aspects of the presentinvention may take the form of a computer program product embodied inone or more computer readable medium(s) having computer readable programcode embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium include the following: an electrical connection havingone or more wires, a portable computer diskette, a hard disk, a randomaccess memory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), an optical fiber, a portablecompact disc read-only memory (CD-ROM), an optical storage device, amagnetic storage device, or any suitable combination of the foregoing.In the context of this document, a computer readable storage medium maybe any tangible medium that can contain, or store a program for use byor in connection with an instruction execution system, apparatus, ordevice.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device. Program codeembodied on a computer readable medium may be transmitted using anyappropriate medium, including but not limited to wireless, wireline,optical fiber cable, RF, etc., or any suitable combination of theforegoing.

In general, a computer program product includes a computer-readablemedium on which one or more computer programs are stored. Execution ofthe computer programs from the computer-readable medium by one or moreprocessors of one or more hardware devices causes a method to beperformed. For instance, the method that is to be performed may be oneor more of the methods that have been described above.

The computer programs themselves include computer program code. Computerprogram code for carrying out operations for aspects of the presentinvention may be written in any combination of one or more programminglanguages, including an object oriented programming language such asJava, Smalltalk, C++ or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The program code may execute entirely on the user's computer,partly on the user's computer, as a stand-alone software package, partlyon the user's computer and partly on a remote computer or entirely onthe remote computer or server. In the latter scenario, the remotecomputer may be connected to the user's computer through any type ofnetwork, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider).

Aspects of the present invention have been described above withreference to flowchart illustrations and/or block diagrams of methods,apparatus (systems) and computer program products according toembodiments of the invention. It will be understood that each block ofthe flowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

It is finally noted that, although specific embodiments have beenillustrated and described herein, it will be appreciated by those ofordinary skill in the art that any arrangement calculated to achieve thesame purpose may be substituted for the specific embodiments shown. Thisapplication is thus intended to cover any adaptations or variations ofembodiments of the present invention. As such and therefore, it ismanifestly intended that this invention be limited only by the claimsand equivalents thereof.

We claim:
 1. A method comprising, responsive to a network fabric loginrequest initiated by a given initiator node: by a network fabricforwarder device, creating a network fabric port and a network fabricaddress for the given initiator node; acquiring a list of one or morenetwork fabric ports of one or more given target nodes associated withthe given initiator node; determining a network fabric address for thegiven target node of each network fabric port within the list; by anetwork fabric controller device, determining, using the network fabricaddresses of the given initiator node and of the given target nodes, oneor more paths between the given initiator node and the given targetnodes through a singly contiguous network fabric and loading the pathsinto a forwarding table of each switching device of a plurality ofswitching devices of the singly contiguous network fabric, such thatmultipaths for transmission of data through the singly contiguousnetwork fabric from the given initiator node and the given target nodesare effected, wherein the network fabric forwarder device and thenetwork fabric controller device are each control-path orprogramming-path connected to each switching device, the network fabriccontroller device does not directly route the data, and the switchingdevices route the data between the given initiator node and the giventarget nodes.
 2. The method of claim 1, wherein the network fabriccontroller device and the network fabric forwarder device areimplemented in a same device.
 3. The method of claim 1, wherein themultipaths are each one of a shared multipath and a disjoint multipath.4. A method comprising, responsive to a network fabric login requestinitiated by a given target node: by a network fabric forwarder device,creating a network fabric port and a network fabric address for thegiven target node; acquiring a list of one or more fabric network portsof one or more given initiator nodes associated with the given targetnode; determining a network fabric address for the given initiator nodeof each network fabric port within the list; by a network fabriccontroller device, determining, using the network fabric address of thegiven target node and of the given initiator nodes, one or more pathsbetween the given initiator nodes and the given target node through asingly contiguous network fabric and loading the paths into a forwardingtable of each switching device of a plurality of switching devices ofthe singly contiguous network fabric, such that multipaths fortransmission of data through the singly contiguous network fabric fromthe given initiator nodes and the given target node are effected,wherein the network fabric forwarder device and the network fabriccontroller device are each control-path or programming-path connected toeach switching device, the network fabric controller device does notdirectly route the data, and the switching devices route the databetween the given initiator nodes and the given target node.
 5. Themethod of claim 4, wherein the network fabric controller device and thenetwork fabric forwarder device are implemented in a same device.
 6. Themethod of claim 4, wherein the multipaths are each one of a sharedmultipath and a disjoint multipath.
 7. A method comprising, responsiveto a network fabric login request initiated by a given initiator node:by a network fabric forwarder device, creating a network fabric port anda network fabric address for the given initiator node; acquiring a listof one or more network fabric ports of one or more given target nodesassociated with the given initiator node; determining a network fabricaddress for the given target node of each network fabric port within thelist; by a network fabric controller device, determining, using thenetwork fabric addresses of the given initiator node and of the giventarget nodes, a path between the given initiator node and the networkfabric forwarder device through the singly contiguous network fabric andloading the path into a forwarding table of each switching device withinthe path, such that multipaths for transmission of data through thesingly contiguous network fabric from the given initiator node and thegiven target nodes are effected, wherein the network fabric forwarderdevice and the network fabric controller device are each control-path orprogramming-path connected to each switching device, the network fabriccontroller device does not directly route the data, and the switchingdevices route the data between the given initiator node and the giventarget nodes.
 8. The method of claim 7, wherein the network fabriccontroller device and the network fabric forwarder device areimplemented in a same device.
 9. The method of claim 7, wherein themultipaths are each one of a shared multipath and a disjoint multipath.